Electrical Switch Snap Action Spring Mechanism
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Solution Overview
Problem
Electrical switches, particularly those for power tools, face issues such as arcing, sparking, and contact welding due to unfavorable conditions like contact bouncing and partial separation, leading to durability and safety concerns.
Innovation Solution
The electrical switch incorporates a resiliently biased presser mechanism with a spring system that accumulates extra biasing force to facilitate faster movement past a barrier, minimizing contact teasing and welding by enabling quicker switching between ON and OFF positions, utilizing a U-shaped presser and a combination of contact and snap springs for enhanced resilience and movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the presser moves slowly past the barrier, then the switching action is gradual and controlled, but contact teasing and welding occur leading to reduced durability and safety
Solution Approach 1:
The spring system dynamically adjusts the presser movement speed by accumulating biasing force during approach to the barrier and releasing it during the transition past the barrier. This creates a variable speed profile where the presser accelerates past the barrier to minimize contact teasing and welding, while still maintaining controlled movement during normal operation.
Solution Approach 2:
The spring system performs preliminary action by accumulating biasing force as the presser approaches the barrier position. This stored energy is then released to propel the presser past the barrier quickly, preventing contact teasing and welding before they can occur. The preliminary accumulation of force ensures the transition is completed rapidly and cleanly.
2Reliability
If a simple spring biasing system is used, then the device complexity is low, but the switching action is insufficient to prevent contact teasing and welding
Solution Approach 1:
The spring system is segmented into multiple components including a first spring for initial biasing and a second spring for additional biasing force accumulation. This segmentation allows each spring to perform a specific function in the sequence of events leading up to and during the barrier transition, enabling reliable contact welding prevention while maintaining reasonable device complexity through modular design.
Solution Approach 2:
Multiple spring elements are merged into a coordinated system where the first and second springs work together to provide the necessary biasing force. The springs are combined in such a way that their forces accumulate sequentially, creating the enhanced switching action needed to prevent contact teasing and welding without requiring an overly complex mechanism.
3Object-affected harmful factors
If the presser moves quickly past the barrier, then contact teasing and welding are minimized, but the switching action may become too rapid causing arcing and sparking
Solution Approach 1:
The presser is designed to skip or rush through the barrier position quickly by utilizing the accumulated spring force. This rapid transition minimizes the time the contacts spend in the partial separation state where teasing and welding occur. The skipping action ensures the presser passes through the critical barrier region so quickly that harmful effects are minimized without causing excessive arcing.
Solution Approach 2:
The spring system maintains continuous biasing force throughout the entire movement cycle, ensuring the presser never loses momentum or control. This continuity of useful action allows the presser to smoothly accelerate past the barrier and maintain controlled movement throughout the switching transition, preventing both contact welding and excessive arcing by eliminating gaps or pauses in the switching action.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a durable and safe switching mechanism that reduces contact teasing and welding, ensuring reliable operation of electrical power tools by enabling faster and more efficient switching, thus addressing the issues of arcing and welding.
Implementation Method 1
a spring having first and second parts acting on the first and second sides of the presser respectively to maintain the presser in a neutral position yet permitting limited extra movement of the presser in one of the first and second directions against the action of the spring as the presser reaches the barrier
Data Source
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AI summary
An electrical switch has at least one fixed contact and a moving contact lever (110) supported for movement between a first (ON) position in contact with said at least one fixed contact and a second (OFF) position out of contact therewith. An operating mechanism moves the moving contact lever between the first and second positions. The operating mechanism includes a resiliently biased presser 150 resiliently pressing upon the moving contact lever for moving the same between the first and second positions while riding in opposite first or second direction past a barrier (110E) associated with the moving contact lever. The presser has opposite first and second sides 153, 154 corresponding to the first and second directions. The operating mechanism includes a spring 170 having first and second parts 173, 174 acting on the first and second sides of the presser respectively to maintain the presser in a neutral position yet permitting limited extra movement of the presser in a rearward direction against the action of the spring as the presser reaches the barrier (110E) in a forward direction, thereby accumulating extra forward biasing force in the spring upon the presser to assist the presser to move relatively faster upon riding past the barrier.